The following relates to the illumination arts, lighting arts, solid state lighting arts, organic light emitting diode (OLED) device arts, and related arts.
Thin film solid state lighting technologies such as thin film electroluminescent (TFEL) devices, organic light emitting diode (OLED) device arts, and so forth have become prevalent display and lighting technologies. These devices can be made thin (e.g., a few millimeters or less in thickness). Additionally, TFEL and OLED devices produce illumination over large area, with the illumination output area sometimes being close to coextensive with the area of the active OLED device film structure. These geometric aspects make thin film solid state lighting devices useful as light sources in “illuminated walls” or other architectural accent or illumination lighting, in undercabinet lighting, and in other types of lighting where space is at a premium and a thin and large-area planar light source is advantageous. Still further, some thin film solid state lighting technologies can be fabricated in flexible form so as to enable flexible lighting sources suitable for use in flexible cards or for mounting on curved support surfaces such as curved pillar walls or the like.
One deficiency in the state of the art lies in the mounting and electrical interconnect technologies for such devices. Although thin film solid state lighting devices can be made thin, large-area, and optionally flexible, these advantages are currently lost to a substantial degree due to size, bulkiness, and rigidity of existing mounting and electrical power input structures. Indeed, in most existing thin film solid state lighting devices the mounting and electrical power input structures are several times thicker than the active light-producing structure, which is typically in the form of a thin film disposed on thin glass or plastic substrates.
For example, one technique currently in use for packaging OLED devices is to employ edge connectors for the electrical input. In such a configuration, the active OLED layers are sandwiched between glass plates or plastic films, and electrodes connecting with edges of the OLED layers extend outside the edges of the sandwiching glass or plastic confinement to form edge connectors. This approach requires an electrically conductive mating structure connecting with the electrodes at the edges of the device. A disadvantage is that the lateral area occupied by the edge electrodes and corresponding mating structures reduces the light emission area of the packaged lighting device, thus reducing the value of the large illumination area of the unpackaged device. For OLED devices which are susceptible to damage from ambient moisture or oxygen, the edge connectors also compromise the hermetic seal at the edges of the confining glass or plastic plates or films.
Other packaging techniques are disclosed in WO 2008/012702 A1 and WO 2008/099305 A1. The approach of WO 2008/012702 A1 employs wireless inductive power transmission in which the OLED device has an “on-board” power receive inductor and on-board power conditioning electronics. Although the on-board inductive coil is described as “planar”, the addition of these on-board component inherently introduces additional complexity, bulk, and thickness to the OLED device.
WO 2008/099305 A1 likewise discloses on-board power conversion and control circuitry which increases bulk and thickness. The electrical connections in WO 2008/099305 A1 are disposed on a backside of the lighting module which connect with bus lines when the lighting module is secured to a printed circuit board mounting structure by on-board clamps, on-board screws, or on-board magnets. The on-board mounting clamps, screws, or magnets contribute still further to the complexity, bulk, and thickness of the OLED lighting devices.